The present invention relates generally to electronic imaging devices, and more particularly to an electrostatic discharge apparatus and method of discharging electrostatic charge for an optical lens.
Hand-held imaging devices are quite common and generally are used to capture either still or video images. Hand-held imaging devices may include analog and digital still cameras and video cameras, for example. These devices have one thing in common: they employ a lens or lens apparatus used to capture an image by focusing light from an object or scene onto a light sensitive imaging material.
A problem encountered in all such imaging devices is the dust that is present in the atmosphere. The majority of atmospheric dust is dielectric in nature. Therefore, dust is attracted to charge objects of both positive and negative polarities. As a result, it may be attracted to and cling to a lens of an imaging device if the lens has any level of electrostatic charge. The problem is greater in hand-held imaging devices because the lenses of such devices do not have a highly conductive or permanent connection to ground. This is in contrast to AC-powered devices, such as desktop computer devices, for example, wherein an electrostatic discharge path is available in an alternating current (AC) ground connection.
The dust or other particulate matter may interfere with image capture and may degrade the image. Dust may cause blurring, distortion, dark spots, etc., in a captured image. In addition, the dust and other particulate matter can damage or scratch the lens if removed improperly. Most image devices instruct a user to remove the dust with a cleaning fluid and a soft cloth. However, the user must be careful not to grind the dust against the lens surface and cause scratching or other damage.
In the prior art, efforts at dust prevention on lens surfaces has been very basic. Generally, a user puts a lens cap on the lens apparatus when not in use. The lens cap prevents dust build up on the surface of the lens. The other prior art approach is to clean the lens frequently to prevent the build up of dust and other particles.
However, the prior art approaches have drawbacks. The first drawback is that the user must remember to put on the lens cap when finished using the device. In addition, the user must remember to clean the lens at proper intervals in order to remove dust and prevent dust build-up. Furthermore, the lens cleaning of the prior art may still scratch or otherwise damage lenses. Moreover, in high dirt conditions it may be impractical to clean the lens frequently enough to prevent build up and/or damage.
Therefore, there remains a need in the art for improvements in apparatus and methods for preventing electrostatic dust accumulation on the lenses of electronic imaging device and preventing damage to such lenses caused by improper cleaning.
A hand-held imaging device is provided according to one embodiment of the invention. The hand-held imaging device comprises a main body and an optical lens mounted on the main body. The device further comprises a transparent conductive coating formed on the optical lens. The device further comprises a conductive pad formed on the main body, with the conductive pad being in electrical contact with the transparent conductive coating. The conductive pad is located on the main body at a region contacted by a user during use of the hand-held imaging device.
A hand-held imaging device is provided according to another embodiment of the invention. The hand-held imaging device comprises a main body and an optical lens mounted on the main body. The device further comprises a transparent conductive coating formed on the optical lens. The device further comprises a conductive path formed on the main body, with the conductive path being in electrical contact with the transparent conductive coating. The device further comprises a conductive pad formed on the main body, with the conductive pad being in electrical contact with the conductive path. The conductive pad is located on the main body at a region contacted by a user during use of the hand-held imaging device.
An electrostatic discharge method for a lens of a hand-held imaging device also is provided according to another embodiment of the invention. The electrostatic discharge method comprises the steps of providing a transparent conductive coating formed on the lens, providing a conductive pad formed on the hand-held imaging device and communicating with the transparent conductive coating, and locating the conductive pad on a region of the hand-held imaging device that a user contacts in order to hold or operate the hand-held imaging device.